Profile Recovery of Impeller using Weld & Belzona 1812 Ceramic Carbide

Our customer was experiencing issues with corrosion & erosion destroying their pump units on a Flue Gas Desulphurisation (FGD) application. Whilst purchasing the uprated impellers – made out of a more resistant Super Duplex, even then the impellers were lasting less than a year before the pumps needed removing from service for overhaul.

The impeller was despatched to Pump Group with the aim of sourcing a more long term and cost effective solution rather than just replacing the impellers with new from the OEM.  Pump Group suggested rebuilding the impeller using specific Belzona Polymeric Coatings designed to withstand such damaging conditions.

The impeller was bead blasted and jet washed clean, and metal inserts were fabricated to roughly rebuild the impeller profile. The inserts were then welded in to position and hard face welding carried out over the edges to increase the strength.

The impeller was shot blasted to remove all possible contaminants and also to achieve a surface profile of SA2.5 @ 75microns which is required for the Belzona to bond correctly to the substrate material. The unit was then salt tested prior to coating to confirm the lack of presence of nitrates and other contaminants which can jeopardise the longevity of the coating.

The surface was rebuilt using Belzona 1812 Ceramic Carbide.  Belzona 1812 was selected as it is a composite material combining extremely hard closely packed abrasion resistant ceramic aggregates in a polymeric binder ideal for the repair and protection of substrates being damaged by particle abrasion.

Once the Belzona was applied (6mm thick) the impeller diameter and neck was machined with a diamond tipped tool to achieve required clearances within the pump. A mandrel was manufactured to allow the rotating element to be dynamically balanced to G2.5 at 1000 rpm.

By utilising Belzona, the impeller was rebuilt in a much shorter period of time, approximately half the cost of a new impeller, and the Belzona 1812 Ceramic Carbide coated impellers achieves twice the life of the OEM impellers.

For more information on how we can utilise our extensive Belzona knowledge and Coating Facilities to assist your company with your operational needs, please contact a member of our Repairs Team on +44 (0)161 864 4678 or via email repairs@pumpgroup.co.uk.